yes it's circular with two cylindrical prongs
Actually there's at least a couple of configurations, but look for
Monroe calculator cables and the non-IBM electric typewriters.
If you've got an old-time typewriter repair shop in your neighborhood
that'd be a real good place to shop. The last typewriter repair
shop in Washington DC closed down last month unfortunately! But
try other old-line stationery supply stores etc too. e.g. NOT
STAPLES, NOT OFFICE DEPOT, etc.
Tim.